Light-sensitive cell



ug. 28, 1934. A F, Q CROWE 1,972,009

LIGHT SENS I'I'IVE CELL original' Filed Maren 25. 1929 Patented Aug. 28, 1934 1,972,009 mehr-SENSITIVE CELL Frederic C. Crowe, Erie, Pa., thirds to S. E. Cauley and of Erie, Pa.

Original application March 349,754, now Patent No. 10, 1930. Divided and assignor of two- C. L. Cauley, both 25, 1929, Serial No. 1,762,470, dated June this` applicationl May 10, 1930, Serial No. 451,483

Y 9 Claims. (CL F75-41.5)

This invention relates to a novel light-sensitive element or condenser particularly adapted for use in the picture transmission system illustrated and described in my application Serial No.

349,754, filed March 25, 1929, Patented June 10,

1930, No. 1,762,470, of which the present application is a division.

The present invention is illustrated in the accompanying drawing in which Fig. 1 is a front 1 view, partly in section, of the novel light-sensitive cell employed in said system; Fig. 2 is a side view and section of Fig. 1 taken on the line 2-2 of that gure; Fig. 3 is an edge view of one of `rthe elements shown in Fig. 1. Fig. 4 is a perspeclltive of amodied form of electrode.

K #Referring to Figure 1, the light-sensitive cell employed in my system comprises a glass envelopey A from which all air or gas has been evacuated to a high degree and in the back of which are sealed a number of fine wires B of square crosssection (see Figure 2). Wires B are arranged in a straight line extending from near the top of the cell to near the bottom, the wires being arranged close together, but insulated from each 2 other. The ends of wires B are smoothed off even with the glass on the inside of the envelope. The wires are preferably square in cross-section and of very small dimension, for example, 40 gauge. A strip of mica is cemented to the back of envelope A over the ends of wire B. Supported on top of mica strip C is a comb like element D, which comprises a stii back member Da and a plurality of thin tooth members Db formed ntegral with the back. The element D may also be 3 a continuous piece without teeth, but of some elastic conductive material as shown at Dc in Fig. 4, just so a capacitive effect is formed. The mica may be omitted using only aix` as a dielectric but in this case the element D must be spaced far enough from the ends of wires B. It must be understood that D and B must be insulated from each other. The comb member may be made from spring brass, or some other metal having some spring to it, and the teeth are of very thin gauge. The comb element D is arranged so that each tooth of thecomb is opposite and overlies the end of one of the wires B. A wire E is connected to the comb element D and is brought out of the envelope as one terminal of the cell. 0 The exposed sides of the teeth of the comb are coated a dull black by anysuitable process. E ach wire B and the corresponding tooth of comb D constitute a small condenser. One terminal of all the condensers are connected together through 'the back of the comb element. i

The action of the light-sensitive cell is as follows: When light falls on theblackened side of the teeth of the comb element, each tooth is Dressed against the mica or where air is used as a dielectric, the tooth is pressed toward itsopposite wire but without, touching it with a tensity proportional to the amount of light falling upon it. If the light is strong, the tooth is pressed heavily against the mica, and the capacity is decreased. If the light ray is weak, the tooth will be pressed lightly and the capacity will be correspondingly greater. When varying intensities of light are impressed on D when D is one continuous elastic conductive substance various sections of D are depressed according to the amount of light, as indicated in Fig. 4.` 'I'he manner in which this'light-sensitive cell is employed is fully disclosed in the application abovereferred to, but it may be used also in any apparatus orsystem, either television or otherwise. In other words it is capable of separate or other uses to which a light-sensitive cell or condenser is appropriate.

The two metallic elements may be used as two single pieces in some systems. By that I mean such a cell could be used in talking motion pictures.

I claim:

. 1. A light-responsive element comprising an electric condenser, one conducting plate of which is blackened andarranged to be exposed to light of varying intensity.

2. A light-responsive element comprising two spaced conducting elements, one ,of said elements being blackened on a surface arranged to be exposed to light.

3. A light-sensitive cell comprising a glass envelope, a light-sensitive electrode within said envelope, and adapted to be exposed to light, and a plurality of opposing electrodes insulated from said rst electrode.

4. A light-sensitive cell comprising an envelope of insulating material, a number of electrodes extending through the wall of said envelope, a strip of insulating material covering 100 the inner ends of said electrodes, andan inner electrode having a corresponding number of lightsensitive teeth resting against the insulating strip opposite the rst mentioned electrodes respectively. 105

.5. A light-sensitive cell comprising a transparent envelope of insulat g material, a series of electrodes extending through the wall of said envelope, a strip of insulating material against the inner ends of said electrodes, and a comb- 110* Lompoc 8. A device of the class described comprising a transparent envelope, spaced conducting elements in said envelope and light responsive means for varying the spaced relationship between said elements.

9.V A device of the class described comprising an envelope which has been evacuated to its greatest operating degree, spaced conducting elements in said envelope and light responsive means for varying the spaced relationship between said elements.

FREDMC C. CROWE. 

